Field of the Invention
The present disclosure relates to a sealer composition for root canal filling for filling a root canal after pulpectomy or after treatment for an infection root canal to prevent invasion of bacteria into the root canal. More specifically, the present disclosure relates to a two-paste type sealer composition for root canal filling which has a hydrophilic property, good wettability to a tooth substance, a low unpleasant odor, a low irritation, a low harmful action, an excellent biocompatibility, a sufficient operation surplus time suitable for root canal filling, and excellent dimensional stability after curing, and wherein a cured product of the sealer composition for root canal filling can be easily removed without damaging the tooth substance when it becomes necessary to remove the cured product after surgery, a difference in various characteristics is not caused because a difference of a technician hardly causes a difference in the amount of collection and in the degree of kneading of two components due to the easiness of kneading, and stable characteristics may be obtained.
Description of the Related Art
In an endodontic procedure, a root canal filling has been performed in order to prevent invasion of bacteria into the root canal and to prevent infection after pulpectomy or after treatment for an infection root canal. In a general technique of the root canal filling, a root canal is sealed by using a gutta-percha point consisting of a gutta-percha and zinc oxide, and a sealer for root canal filling, at the same time. Requirements for a sealer for root canal filling include an excellent biocompatibility such as good wettability or adhesion to the root canal tooth containing a large amount of water and a low harmful action to an apical periodontal tissue, fluidity suitable for root canal filling, a sufficient operation surplus time suitable for root canal filling, little shrinkage at the time of curing, excellent dimensional stability after curing, a high X-ray contrast property, excellent removability of a cured product in re-treatment of a root canal, and the like. Furthermore, it takes particularly a long time to treat in a treatment for a tooth having a plurality of root canals. Therefore, a low odor is also required because a burden is imposed on the patient when there is an unpleasant odor in a sealer for root canal filling.
On the other hand, various sealers for root canal filling have been proposed so far, but each of the following problems remains in the proposed sealers for root canal filling. That is, a zinc oxide-eugenol based sealer for root canal filling consisting of a powder material containing zinc oxide as a main component and a liquid material containing eugenol as a main component is the most commonly used in clinical practice. However, the zinc oxide-eugenol based sealer for root canal filling has a strong unpleasant odor which is peculiar to eugenol, poor wettability to the tooth because of hydrophobicity. Furthermore, there is concern about a harmful action to the living body caused by eugenol.
Further, in the powder-liquid type sealer for root canal filling wherein a powder component and a liquid component are kneaded and used, since the measurement of each component is complicated and the amount of collection tends to vary, a difference in a property of a kneaded material may be caused by every collection. Therefore, there is a risk of adversely affecting a filling property to a root canal and of causing a difference in various characteristics of a cured product. Furthermore, since the operation of kneading powder and liquid is complicated and requires a skill, a difference in various characteristics of a cured product may be easily caused by a difference of a technician. Therefore, it is difficult to obtain stable various characteristics. For this reason, in recent years, two-paste type tends to be more preferably used than powder-liquid type which may obtain stable various characteristics because the operation of kneading is easy and a difference of a technician hardly causes a difference in the amount of collection and in the degree of kneading of two components.
A fatty acid based sealer for root canal filling consisting of a powder material containing zinc oxide as a main component and a liquid material containing, as a main component, an organic unsaturated fatty acid, an organic saturated fatty acid and a multivalent alcohol has been proposed as a sealer for root canal filling which improves a problem in a zinc oxide-eugenol based sealer for root canal filling and reduces an odor and a harmful action to the living body (Japanese Unexamined Patent Application Publication No. S60-181004). However, this sealer also has a characteristic odor, and because this sealer is hydrophobic, this sealer also has poor wettability to the tooth substance.
A calcium phosphate/apatite based sealer for root canal filling consisting of a powder material containing α-TCP, and hydroxyapatite as a main component and a liquid material containing a polycarboxylic acid aqueous solution as a main component (Japanese Unexamined Patent Application Publication No. S62-19508), and a calcium phosphate based sealer for root canal filling consisting of a powder material containing tetra calcium phosphate and secondary calcium phosphate as a main component and a liquid material containing a polycarboxylic acid aqueous solution as a main component (Japanese Unexamined Patent Application Publication No. H2-250811) have been proposed as a sealer for root canal filling having an excellent biocompatibility. Although these sealers are hydrophilic and have good wettability to the tooth substance, these have a low X-ray contrast property, an acid odor due to the polycarboxylic acid, and an irritation to an apical periodontal tissue caused by a strong acidity immediately after kneading.
A dental sealer kit for root canal filling consisting of a resin based sealer for root canal filling containing a monofunctional polymerizable monomer including a polymerizable monomer having an acidic group, a polymerization initiator, an X-ray contrasting filler, and a polymer that swells with the monofunctional polymerizable monomer as a main component and a tooth surface treatment agent suitable for a combination with the resin based sealer for root canal filling, has been proposed as a sealer system for root canal filling having moderate fluidity, a long operation surplus time, and an excellent X-ray contrast property and an excellent sealing property (Japanese Patent Publication No. 3638615). However, this sealer requires tooth surface treatment and therefore the operation is complicated. In addition, there is a concern that a harmful action to the living body due to dissolution of unpolymerized polymerizable monomer and a formation of a gap between the sealer and the tooth substance due to polymerization shrinkage. Furthermore, since the strength of the cured product is high, it is difficult to remove the cured product in re-treatment of a root canal.
Furthermore, because all sealers for root canal filling shown above are powder liquid type, there are problems in collecting and kneading peculiar to the powder liquid type described above.
On the other hand, a glass ionomer based root sealer for root canal filling in which a first paste containing polycarboxylic acid, a filler which does not react with polycarboxylic acid and water, and a second paste containing a fluoroaluminosilicate glass powder and a filler which does not react with polycarboxylic acid, a water soluble thickener and water, are kneaded for use, has been proposed as a sealer for root canal filling having an excellent sealing property, an excellent biocompatibility, excellent removability of a cured product in re-treatment of a root canal, and easiness of collecting and kneading operation (Japanese Unexamined Patent Application Publication No. 2003-183111). However, because this sealer has a high curing rate, it does not have a sufficient operation surplus time. Further, this sealer has an acid odor due to the polycarboxylic acid, and an irritation to an apical periodontal tissue caused by a strong acidity immediately after kneading.